Middle and high school students who used electronic cigarettes were more likely to smoke real cigarettes and less likely to quit than students who did not use the devices, a new study has found. They were also more likely to smoke heavily. But experts are divided about what the findings mean.

The study’s lead author, Stanton Glantz, a professor of medicine at the University of California, San Francisco, who has been critical of the devices, said the results suggested that e-cigarettes, whose use is growing rapidly among youth and adults, were leading to less quitting, not more.

“The use of e-cigarettes does not discourage, and may encourage, conventional cigarette use among U.S. adolescents,” the study concluded.

It was published online in the journal JAMA Pediatrics on Thursday.

But other experts said the data did not support that interpretation. They said that just because e-cigarettes are being used by youths who smoke more and have a harder time quitting, it does not mean that the devices themselves are the cause of those problems. It is just as possible, they said, that young people who use the devices were heavier smokers to begin with or would have become heavy smokers.

“The data in this study do not allow many of the broad conclusions that it draws,” said Thomas J. Glynn, a researcher at the American Cancer Society.

The study is likely to further stir the debate over what electronic cigarettes mean for the nation’s 45 million smokers, about 3 million of whom are middle and high school students. Some experts worry that e-cigarettes are a gateway to smoking real cigarettes for young people, although most say the data are too skimpy to settle the issue. Others hope the devices could be a path to quitting.

So far, the overwhelming majority of young people who use e-cigarettes also smoke real cigarettes, a large federal survey published last year found.

Still, while e-cigarette use among youth doubled from 2011 to 2012, cigarette smoking for youth has continued to decline. The smoking rate hit a record low in 2013 of 9.6 percent, down by two-thirds from its peak in 1997.

The new study drew on broad federal survey data from more than 17,000 middle school and high school students in 2011 and more than 22,000 in 2012. But instead of following the same students over time - which many experts say is crucial to determine whether there has been a progression from e-cigarettes to actual smoking - the study examined two different groups of students, essentially creating two snapshots.

Glantz says that his findings show that use of e-cigarettes can predict who will go on to become an established smoker. Students who said they had experimented with cigarettes - that is, taken at least one puff - were much more likely to become established smokers if they also used e-cigarettes, he said.

“One of the arguments that people make for e-cigarettes is that they are a way to cut down on the smoking of cigarettes, but the actual use pattern is just the opposite,” he said.

But David Abrams, executive director of the Schroeder Institute for Tobacco Research and Policy Studies at the Legacy Foundation, an anti-smoking research group, said the study’s data did not support that conclusion.

“I am quite certain that a survey would find that people who have used nicotine gum are much more likely to be smokers and to have trouble quitting, but that does not mean that gum is a gateway to smoking or makes it harder to quit,” he said.

He argued that there were many possible reasons that students who experimented with e-cigarettes were also heavier smokers - for example, living in a home where people smoke, belonging to a social circle where smoking is more common, or abusing drugs or alcohol.

The study did have a bright spot: Youths who used e-cigarettes were more likely to plan to quit smoking. Abrams highlighted that finding, but said it was impossible to tell whether students who planned to quit actually did, because the data did not track it.

To post a comment, log into your chosen social network and then add your comment below. Your comments are subject to our Terms of Service and the privacy policy and terms of service of your social network. If you do not want to comment with a social network, please consider writing a letter to the editor.